1. Field of the Invention
This invention relates to vehicle height adjustment and more particularly, in a preferred embodiment to apparatus and methods for automatic adjustment of front suspension height of new vehicles equipped with front-end torsion bars.
2. Description of the Prior Art
In prior art front suspension height adjustment schemes, means are employed to compensate for initial height loss of the front suspension system of new vehicles due to settling of the components. Typically, new vehicle suspension components will settle most during the first 2,000 miles of operation causing front height loss. To compensate for this initial front height loss, the automobile manufacturers usually have their assembly plant technicians set front suspension heights somewhat higher than the vehicle specifications prescribed.
Prior to setting the front end, the vehicle must be jounced or rebounded in an attempt to remove and eliminate the frictional effects of the front suspension components. Then after eliminating the frictional effects, the height of the vehicle is adjusted prior to making any of the other front suspension adjustments such as caster, camber, toe-in, etc.
With respect to vehicles equipped with torsion bars, under assembly line conditions, the most convenient manner for eliminating friction effects of the components, primarily the rubber grommets and bushings, has been to raise the vehicle slightly off the front wheels by contacting a frame member with a power lifting device and then removing the lift, allowing the wheels and front suspension to bounce. This rebounding approach does, sometimes eliminate some of the frictional effects but such an approach does not emulate the settling effects that would occur over 2,000 miles of vehicle operation.
Some automobile manufacturers prescribe manually jouncing each vehicle vigorously several times. They recommend that the front bumper be used and the front bumper amplitude (total vehicle movement during jouncing) be at least 4 inches, which may require the service of two people to achieve the result. Once the vehicles have been jounced or rebounded, manual adjustments of the height of the vehicle take place.
Such jouncing and rebounding techniques appear to achieve inconsistent amounts of correction of the front suspensions of the new vehicles on the assembly lines and the manual adjusting procedure of vehicle height is time consuming. A search for various other means to reduce frictional effects in new vehicle front ends and for more convenient and efficient means for adjusting vehicle height was initiated. This search resulted in the novel apparatus and method of the present invention.